Mechanisms of Nrf2/HO-1 pathway up-regulation induced by pu-erh black tea extract supplementation for quinocetone-treated Sprague-Dawley rats

Pu-erh tea is a special post-fermented tea product that contains various compounds. Quinocetone (QCT) has been used as a veterinary drug in P.R. China. However, QCT has been proven to cause oxidative DNA damage, inflammation, and apoptosis. We have used Pu-erh black tea extract (BTE) as an intervention for QCT-treated SD rats and analyzed its protective effect. Our data demonstrated that BTE improved QCT-induced functional and organic liver damage. This protective effect was accomplished by activating the Nrf2/HO-1 pathway expression and the potential mechanism consisted in the activation of the extracellular signal-regulated kinase (ERK) pathway by polyphenols contained in BTE. Moreover, some flavonoids and quinone (also contained in BTE) might effectively activate Nrf2/HO-1 pathway expression and protect SD rats from oxidative stress. Thus, the protective effect of BTE against QCT-induced oxidative damage demonstrated new insights into the antioxidative mechanisms of Pu-erh tea.